Wrong number of template arguments

I’m unable to install rstan and see the error

/Users/jacobcvt12/.Rlibs/StanHeaders/include/stan/math/rev/mat/fun/Eigen_NumTraits.hpp:200:77: error: wrong number of template arguments (8, should be 9)
  200 |                                      RhsStorageOrder, ConjugateRhs, ColMajor> {

I’m using g++ 11.1.0.

Hi, sorry to hear you are having problems.
What system are you on? Which version of Stan are you using? Does any of the steps at Stan installed but example code fails to run. Something about Rtools? help you resolve this?